DE102021121678B3 - Method for producing a green body with a press, and a press - Google Patents

Abstract

Process for producing at least one green body (1) using a press (2).Press (2) for producing at least one green body (1). The press (2) comprises a die (3) with a capacity (4) for a powdered material (5). The die (3) comprises a rigid first press jacket (10), a second press jacket (11) made of an elastically deformable material and a rigid press ring (12). The press (2) further comprises at least one first closing element (13) for closing the first end face (7), at least one second closing element (14) for closing the second end face (8) and at least one punch (15) opposite the die (3) can be moved at least between an initial position (16) and a pressing position (17) and is arranged in such a way that in the pressing position (17) it at least partially displaces the second material of the second press jacket (11).

Description

The invention relates to a method for producing at least one green compact using a press and a press, in particular a press for producing green compacts. With the press, in particular, possibly sinterable, green compacts are produced from powdered material. In particular, metallic and/or ceramic powders can be pressed into green compacts with the press.

In known methods or presses, which are used to produce thin-walled, hollow-cylindrical components, a powdered material is arranged in a hollow-cylindrical receiving volume of a die. The matrix includes a rigid compression ring surrounding the receiving volume. The receiving volume extends in a radial direction between the compression ring and a core rod. For the production of certain green compacts, the core rod consists of an elastically deformable material and, together with the material, is subjected to a pressing pressure on one end face by a stamp that can be moved in an axial direction. For the production of other green compacts, an elastically deformable, ring-shaped press jacket is arranged between the die and a stiff core rod, which is subjected to a pressing pressure via one end face, together with the material, by a stamp that can be moved in an axial direction. The elastically deformable core rod or the press jacket transfers the pressing pressure of the stamp applied in the axial direction by deformation to the powdery material compacted by the stamp in the radial direction.

From the WO 2008/036926 A1 , the JP 2016-168 676 A as well as the U.S.A. 4,496,299 an elastically deformable, ring-shaped press shell is known in each case, which is arranged between the die and a rigid core rod.

From the JP 2010-274 288 A an elastically deformable core rod is known, which can be deformed by stamps and thus transmits a pressing pressure to a hollow-cylindrical press jacket, which consists of a non-elastic material.

From the EP 1 602 473 A1 a device for producing a powder compact is known, wherein a die has a spreading element.

When the green body relaxes, that is to say when the ram moves back, the elastically deformable core rod or the press jacket springs back in the axial direction into an initial shape. This springback is significantly stronger than a springback of the green body. Due to the friction between the core rod or the pressing jacket and the powdered material, an edge is also formed on the front side of the green body facing the punch, protruding in the radial direction into the elastically deformable material. During the pressing of the powdered material, e.g. Frictional forces between the core rod or the press jacket and the material or the green body, which are not reduced even if the core rod or the press jacket springs back into its original shape. These circumstances mean that the green body can fail as part of the relaxation as a result of the shearing forces acting on the green body.

Proceeding from this, it is the object of the present invention to at least partially solve the problems described with reference to the prior art. In particular, a method and a press are to be provided with which, in particular, hollow-cylindrical, thin-walled green compacts can also be produced.

To solve this problem, a method according to the features of patent claim 1 and a press according to the features of patent claim 14 are proposed. Advantageous developments are the subject matter of the dependent patent claims. The features listed individually in the patent claims can be combined with one another in a technologically meaningful manner and can be supplemented by explanatory facts from the description and details from the figures, with further embodiment variants of the invention being shown.

A method for producing at least one green compact using a press is proposed. The press is in particular a powder press, ie designed to be suitable for pressing a powdered material into a green compact.

• • eine Matrize mit einem Aufnahmevolumen für einen pulverförmigen Werkstoff; wobei sich das Aufnahmevolumen entlang einer axialen Richtung zwischen einer ersten Stirnseite und einer zweiten Stirnseite erstreckt; wobei die Matrize
  • o einen, in einer quer zur axialen Richtung verlaufenden radialen Richtung innerhalb oder außerhalb des Aufnahmevolumens angeordneten und an das Aufnahmevolumen angrenzenden ringförmigen ersten Pressmantel, der aus einem nicht elastisch verformbaren ersten Material gebildet ist;
  • o einen, in der radialen Richtung benachbart zum ersten Pressmantel angeordneten zweiten Pressmantel, der aus einem elastisch verformbaren zweiten Material gebildet ist; sowie
  • ◯ einen Pressring, der in der radialen Richtung benachbart zu der Gruppe, umfassend den ersten Pressmantel, den zweiten Pressmantel und das Aufnahmevolumen, angeordnet ist; aufweist; wobei der erste Pressmantel entlang der radialen Richtung zwischen dem Aufnahmevolumen und dem zweiten Pressmantel angeordnet ist;
  • • mindestens ein erstes Schließelement zum Verschließen der ersten Stirnseite und zum Verpressen des Werkstoffs;
  • • mindestens eine zweites Schließelement zum Verschließen der zweiten Stirnseite und zum Verpressen des Werkstoffs;
  • • mindestens einen Stempel, der gegenüber der Matrize zumindest zwischen einer Ausgangsposition und einer Pressposition verfahrbar ist.

The press includes at least the following:

• • a die with a receiving volume for a powdered material; wherein the receiving volume extends along an axial direction between a first face and a second face; where the die
  • an annular first press jacket, which is arranged in a radial direction running transversely to the axial direction inside or outside the receiving volume and adjoins the receiving volume and is formed from a non-elastically deformable first material;
  • o a second press jacket arranged adjacent to the first press jacket in the radial direction and formed of an elastically deformable second material; such as
  • ◯ a pressing ring arranged adjacent in the radial direction to the group comprising the first pressing shell, the second pressing shell and the storage volume; having; wherein the first press jacket is arranged along the radial direction between the receiving volume and the second press jacket;
  • • at least one first closing element for closing the first end face and for pressing the material;
  • • at least one second closing element for closing the second end face and for pressing the material;
  • • at least one punch which can be moved relative to the die at least between an initial position and a pressing position.

1. a) Bereitstellen der Presse, wobei das Aufnahmevolumen an der ersten Stirnseite durch das erste Schließelement verschlossen und der mindestens eine Stempel in der Ausgangsposition angeordnet ist;
2. b) Einfüllen des pulverförmigen Werkstoffes in das Aufnahmevolumen;
3. c) Schließen der zweiten Stirnseite durch das zweite Schließelement;
4. d) Verfahren der Schließelemente und Verpressen des Werkstoffs;
5. e) Verfahren des Stempels in die Pressposition, wobei der Stempel in der Pressposition den zweiten Pressmantel kontaktiert und dabei das zweite Material zumindest teilweise verdrängt, so dass eine Presskraft des Stempels auf den zweiten Pressmantel und davon ausgehend über den ersten Pressmantel auf den pulverförmigen Werkstoff übertragen wird;
6. f) Verpressen des Werkstoffs zu einem Grünling, wobei der Stempel unabhängig von den Schließelementen verfahrbar ist bzw. verfahren wird.

The procedure comprises at least the following steps:

1. a) providing the press, wherein the receiving volume on the first end side is closed by the first closing element and the at least one stamp is arranged in the starting position;
2. b) filling the powdered material into the receiving volume;
3. c) closing the second end face by the second closing element;
4. d) moving the closing elements and pressing the material;
5. e) Movement of the stamp into the pressing position, with the stamp in the pressing position contacting the second press shell and thereby at least partially displacing the second material, so that a pressing force of the stamp is transferred to the second press shell and, starting from there, via the first press shell to the powdery material becomes;
6. f) Pressing the material to form a green part, with the stamp being able to be moved or being moved independently of the closing elements.

The above (non-exhaustive) division of the method steps into a) to f) is primarily intended to serve only as a distinction and does not impose any order and/or dependency. The frequency of the process steps can also vary. It is also possible for method steps to at least partially overlap one another in terms of time. In particular, z. B. the steps d) and e) in different order and / or at least partially parallel to each other. In particular, step f) occurs as a result of steps d) and e). In particular, steps a) through f) are performed in the order listed.

The press is in particular a powder press for the production of green compacts. In particular, sinterable green compacts are produced with the press, ie green compacts that can be sintered after the pressing process. In particular, metallic powders and/or ceramic powders can be pressed into green compacts with the press. The powdered material can also contain additives or z. B. combined with solid parts or connected as part of the process.

In particular, the press includes a die with a capacity for a powdered material. The receiving volume extends along an axial direction between a first end face and a second end face.

The press further comprises at least one first closing element for closing the first end face, at least one second closing element for closing the second end face and at least one punch which can be moved relative to the die at least between an initial position and a pressing position.

The closing elements can be embodied as stamps or stationary components of the press (that is to say that are immovable in relation to the receiving volume). The closing elements can be made in one piece or in several pieces. In particular, at least one of the closing elements is designed as a movable stamp for pressing the material.

The die comprises at least a first press shell, a second press shell and a press ring.

The first press jacket is ring-shaped, possibly hollow-cylindrical, and is arranged in a radial direction running transversely to the axial direction inside or outside of the receiving volume. The first press jacket is arranged adjacent to the receiving volume. The first press jacket is formed from a non-elastically deformable first material. The first press jacket is arranged in particular directly adjacent to the receiving volume, so that it contacts the powdered material or the green compact.

In particular, the first press jacket extends along the axial direction at least beyond the position of the first closing element (e.g. at least during step b), so that the receiving volume is defined by the first closing element and the first press jacket and the to be pressed transmitting material can be arranged in the receiving volume. In particular, the first press jacket extends beyond the position of the second closing element during step d), so that the receiving volume is defined by the closing elements and the first press jacket at least during step d). from the first end face to the second end face of the receiving volume.

In particular, the first closing element and/or the second closing element extend in a radial direction over the receiving volume and up to the first press jacket. In particular, the closing elements are guided over an inner or outer peripheral surface of the first press jacket in relation to the radial direction.

The second press sleeve is arranged (immediately) adjacent to the first press sleeve in the radial direction. In particular, the second press jacket makes contact with the first press jacket. The second press jacket is formed in particular from an elastically deformable second material.

In particular, the second press jacket extends along the axial direction at least, preferably precisely, from the first end face to the second end face of the receiving volume. In particular, the second press jacket extends in at least one axial direction, preferably in both axial directions, over the end faces of the receiving volume.

In particular, the first press jacket extends along at least one axial direction, preferably along both axial directions, beyond the second press jacket.

The second press jacket is particularly ring-shaped, possibly hollow-cylindrical, especially when it is arranged outside the first press jacket in the radial direction, but also when it is arranged inside the first press jacket in the radial direction.

In particular, when the second press jacket is arranged outside the first press jacket in the radial direction, it is arranged between the press ring and the first press jacket in the radial direction.

The second press jacket is designed as a solid body (that is to say not ring-shaped), possibly cylindrical, in particular when it is arranged inside the first press jacket in the radial direction.

In particular, when the second press jacket is arranged outside the first press jacket in the radial direction, it is arranged between the press ring and the first press jacket in the radial direction.

In particular, when the accommodating space is located outside the first press shell in the radial direction, it is located between the press ring and the first press shell in the radial direction.

In particular, the pressing ring is arranged in the radial direction adjacent to the group comprising the first pressing shell, the second pressing shell and the accommodation volume.

In particular, the compression ring extends along the axial direction at least, preferably precisely, from the first end face to the second end face of the receiving volume. In particular, the press ring extends in at least one axial direction, preferably in both axial directions, over the end faces of the receiving volume and/or over the first press jacket and/or over the second press jacket.

The press ring is in particular made of a non-elastically deformable material.

A non-elastically deformable material is z. B. a metallic material such. B. a steel material or a metallic alloy. In contrast, an elastically deformable material in this context z. B. a plastic, in particular a non-metallic and / or non-ceramic material.

The first press jacket is arranged in particular along the radial direction between the receiving volume and the second press jacket.

In step a), the press is prepared, with the receiving volume being closed off on the first end face by the first closing element and the ram being arranged in the initial position. The first closing element thus forms in particular the first end face of the accommodation volume. The receiving volume is designed to be closed, in particular except for the filling opening for the powdered material. The recording volume is defined in particular by the components of the press, z. B. by the first press shell, the press ring, at least one closing element, a core rod, an ejector, etc. The receiving volume includes in particular a larger volume than the volume of the green body produced, since this is produced by pressing and compacting the powdery material.

In step b), the powdered material is filled into the receiving volume. The filling can e.g. B. done on the second end face.

In step c), the second end face is closed by the second closing element. In particular, the second closing element forms the second end face of the accommodation volume. The volume of the receiving volume is thus defined in step c). The recording volume is reduced or increased by the movement of the closing elements.

In step d), the closing elements are moved and the material is pressed. The recording volume is gradually reduced.

In step e), the at least one stamp is moved into the pressing position. The punch moves in particular along the axial direction or else along a radial direction, a circumferential direction or any combination of the directions mentioned above.

In particular, the stamp contacts the second press shell in the pressing position and thereby at least partially displaces the second material, so that a pressing force of the stamp is transmitted to the second press shell and, starting therefrom, via the first press shell to the powdery material.

The contacting of the second material of the second press casing takes place in particular successively during the movement of the at least one stamp. The second material is thus increasingly displaced during the process. The displaced volume of the second material now serves to support the first press jacket, which is subjected to the pressing force applied by the closing elements via the compacted material. The first material of the first press jacket can therefore not deviate in particular in the radial direction or deviate from the pressing force of the closing elements, but is supported by the second material with a supporting force. If necessary, the first press jacket is moved towards the receiving volume and reduces it.

The material is pressed and increasingly compacted via the first press cover (or via the second press cover) and the closing elements.

In step f), the material is pressed to form a green compact, with the stamp being able to be moved or being moved independently of the closing elements.

In particular, there is no such. B. mechanical coupling between the stamp and the closing elements. In particular, the at least one stamp can be moved independently of the closing elements and subjected to a pressing force.

In particular, the capacity is reduced solely by moving the closing elements. In particular, a distance between the end faces changes during step d) or additionally during step e), ie during the displacement of the second material by the at least one stamp.

With the method described, it can be achieved in particular that the green compact is not damaged when the shaping press components, in this case the closing elements and the first press jacket, are relieved of stress. In particular, the green compact detaches itself from the wall of at least the first press jacket due to the springback of the green compact and the first press jacket, which can relax when the at least one punch moves back into the starting position in the radial direction.

There is therefore no relative movement between the press component and the green body that generates a shearing effect. In addition, a high degree of dimensional accuracy of the green compact (with regard to a predetermined geometry) can be achieved. The formation of an end edge on the green compact, which is known from the prior art, does not occur here in particular.

In particular, the at least one stamp is arranged at a distance from the first press jacket in the pressing position. In particular, the at least one stamp is arranged at a distance from the first press jacket in the radial direction. If necessary, the at least one stamp contacts the pressing ring or is arranged adjacent to it, at least in the pressing position.

In particular, the second material comprises a polymer material. In particular, the other materials of the other components of the press, ie z. B. the at least one stamp, or each stamp, the press ring, the first press jacket, the closing elements, each a metallic material, z. B. a steel material.

In particular, after step f), in a step g), the at least one stamp is moved from the pressing position back to the starting position, with the green body being relaxed exclusively in the radial direction.

During step g), the closing elements in particular are not moved, at least in relation to the axial direction. The one produced in step f). The green compact is therefore relaxed in relation to the radial direction.

In particular, after step f), in a step g), the green compact is successively relaxed by moving the at least one punch and at least one of the closing elements, with the green compact being relaxed both in the radial direction and in the axial direction. In particular, a coordinated movement of the at least one stamp and the closing elements can be used to control relaxation of the green compact, so that stresses in the green compact can be gradually reduced.

In particular, during the displacement of the second material by the ram, ie during step e), the closing elements are positioned in a stationary manner, ie are not moved. In particular, therefore, the movement of the closing elements has already been completed before step e) or is continued after step e).

In particular, steps d) and e) are carried out at least partially at the same time, i. H. Stamps and closing elements are at least partially moved parallel to one another in terms of time.

In particular, the press includes a plurality of stamps that are used in step e) to displace the second material. The stamps can be moved simultaneously or in a fixed order. The stamps can be moved into the second material from different directions. With the use of several stamps, the distribution of the pressing force on the first press cover can in particular be evened out.

In particular, the at least one punch has an end face that contacts the second material in step e), the end face having a contour through which the second material is displaced in the radial direction toward the first press jacket. The contour can B. include a conical, so compared to the axial or the radial direction inclined surface. The surface can be straight or flat, optionally curved only in the circumferential direction. However, the surface can also have a curved contour in a plane that runs parallel to the axial direction and to the radial direction.

In particular, the second material is displaced in a targeted manner by the end face in the direction of the first press casing, so that a uniform distribution of the pressing force introduced into the second material via the at least one stamp is made possible.

In particular, at least one of the closing elements is at least partially designed as an ejector, so that the green compact can be displaced by the ejector along the axial direction after step f) and preferably after step g) in a further step h). The ejector is designed in particular in the manner of a stamp, with which the green body can be removed from the receiving space.

In particular, the receiving volume is ring-shaped. The receiving volume is preferably hollow-cylindrical.

In particular, the receiving volume is arranged in the radial direction inside the first press jacket, and thus also inside the second press jacket and the press ring. Alternatively, the receiving volume can also be arranged in the radial direction outside of the first press jacket and thus outside of the second press jacket, but inside the press ring.

• • eine Matrize mit einem Aufnahmevolumen für einen pulverförmigen Werkstoff; wobei sich das Aufnahmevolumen entlang einer axialen Richtung zwischen einer ersten Stirnseite und einer zweiten Stirnseite erstreckt; wobei die Matrize
  • o einen, in einer quer zur axialen Richtung verlaufenden radialen Richtung innerhalb oder außerhalb des Aufnahmevolumens angeordneten und an das Aufnahmevolumen angrenzenden ringförmigen ersten Pressmantel, der aus einem nicht elastisch verformbaren ersten Material gebildet ist;
  • o einen, in der radialen Richtung benachbart zum ersten Pressmantel angeordneten zweiten Pressmantel, der aus einem elastisch verformbaren zweiten Material gebildet ist; sowie
  • ◯ einen Pressring, der in der radialen Richtung benachbart zu der Gruppe, umfassend den ersten Pressmantel, den zweiten Pressmantel und das Aufnahmevolumen, angeordnet ist;
  aufweist; wobei der erste Pressmantel entlang der radialen Richtung zwischen dem Aufnahmevolumen und dem zweiten Pressmantel angeordnet ist;
• • mindestens ein erstes Schließelement zum Verschließen der ersten Stirnseite und zum Verpressen des Werkstoffs;
• • mindestens eine zweites Schließelement zum Verschließen der zweiten Stirnseite und zum Verpressen des Werkstoffs;
• • mindestens einen Stempel, der gegenüber der Matrize zumindest zwischen einer Ausgangsposition und einer Pressposition unabhängig von den Schließelementen verfahrbar und dabei so angeordnet ist, dass er in der Pressposition das zweite Material zumindest teilweise verdrängt.

A press for producing at least one green compact is proposed. The press includes at least

• • a die with a receiving volume for a powdered material; wherein the receiving volume extends along an axial direction between a first face and a second face; where the die
  • an annular first press jacket, which is arranged in a radial direction running transversely to the axial direction inside or outside the receiving volume and adjoins the receiving volume and is formed from a non-elastically deformable first material;
  • o a second press jacket arranged adjacent to the first press jacket in the radial direction and formed of an elastically deformable second material; such as
  • ◯ a pressing ring arranged adjacent in the radial direction to the group comprising the first pressing shell, the second pressing shell and the storage volume;
  having; wherein the first press jacket is arranged along the radial direction between the receiving volume and the second press jacket;
• • at least one first closing element for closing the first end face and for pressing the material;
• • at least one second closing element for closing the second end face and for pressing the material;
• • at least one stamp which can be moved relative to the die at least between a starting position and a pressing position independently of the closing elements and is arranged in such a way that it at least partially displaces the second material in the pressing position.

The statements on the process described that relate to the press can be transferred to the press.

In particular, the die is held in the press via an adapter. in particular, the die is not moved in the press during the process described. In particular, only the other components of the press, e.g. B. the closing elements, the at least one punch, the core rod, the ejector moves relative to the die.

In particular, the press has a system for data processing, e.g. B. a control device, which is suitably equipped, configured or programmed to carry out the method described or which executes the method. In particular, the system has means that are suitably equipped, configured or programmed to carry out the method or that carry out the method.

The control unit or the means includes or include z. B. a processor and a memory in which instructions to be executed by the processor are stored, as well as data lines or transmission devices which enable transmission of instructions, measured values, data or the like between the listed elements.

A computer program is also proposed, comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method described or the steps of the method described.

A computer-readable storage medium is also proposed, comprising instructions which, when executed by a computer, cause the computer to carry out the method described or the steps of the method described.

The statements on the method can be transferred in particular to the press, the system for data processing and/or the computer-implemented method (ie the computer program and the computer-readable storage medium) and vice versa.

The use of indefinite articles (“a”, “an”, “an” and “an”), particularly in the claims and the description reflecting them, is to be understood as such and not as a numeral. Correspondingly introduced terms or components are to be understood in such a way that they are present at least once and in particular can also be present several times.

As a precaution, it should be noted that the numerals used here (“first”, “second”, ...) primarily (only) serve to distinguish between several similar objects, sizes or processes, i.e. in particular no dependency and/or sequence of these objects, sizes or make processes mandatory for each other. Should a dependency and/or order be necessary, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described embodiment. If a component can occur several times (“at least one”), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

• 1: eine bekannte Presse in einer Seitenansicht im Schnitt, vor einem Pressvorgang;
• 2: die Presse nach 1 in einer Seitansicht im Schnitt, während eines Pressvorgangs;
• 3: eine erste Ausführungsvariante einer Presse in einer Seitenansicht im Schnitt, während Schritt a) des Verfahrens;
• 4: die Presse nach 3 in einer Seitenansicht im Schnitt, während der Schritte b) und c) des Verfahrens;
• 5: die Presse nach 3 und 4 in einer Seitenansicht im Schnitt, während der Schritte d), e) und f) des Verfahrens;
• 6: die Presse nach 3 bis 5 in einer Seitenansicht im Schnitt, während Schritt g) des Verfahrens;
• 7: die Presse nach 3 bis 6 in einer Seitenansicht im Schnitt, während Schritt g) des Verfahrens;
• 8: die Presse nach 3 bis 7 in einer Seitenansicht im Schnitt, während Schritt h) des Verfahrens; und
• 9: eine zweite Ausführungsvariante einer Presse in einer Seitenansicht im Schnitt, während der Schritte d), e) und f) des Verfahrens.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be pointed out that the invention should not be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. Show it:

• 1 : a known press in a side view in section, before a pressing operation;
• 2 : the press after 1 in a side view in section, during a pressing process;
• 3 : a first embodiment variant of a press in a side view in section, during step a) of the method;
• 4 : the press after 3 in a sectional side view, during steps b) and c) of the method;
• 5 : the press after 3 and 4 in a sectional side view, during steps d), e) and f) of the method;
• 6 : the press after 3 until 5 in a sectional side view, during step g) of the method;
• 7 : the press after 3 until 6 in a sectional side view, during step g) of the method;
• 8th : the press after 3 until 7 in a sectional side view, during step h) of the method; and
• 9 : a second variant embodiment of a press in a sectional side view, during steps d), e) and f) of the method.

1 shows a known press 2 in a side view in section, before a pressing operation. 2 shows the press 2 1 in a side view in section, during a pressing process. the 1 and 2 are described together below.

The press 2 comprises a die 3 with a rigid compression ring 12 surrounding a receiving volume 4. The receiving volume 4 extends in a radial direction 9 between the compression ring 12 and a rigid core rod 21. For the production of the green body 1, an elastically deformable, ring-shaped first press jacket 10 is arranged between the press ring 12 and the core rod 21, which, together with the material 5 filled into the receiving space 4, is subjected to a pressing pressure via a first end face 7 by a stamp 15 that can be moved in an axial direction 6. The elastically deformable first press casing 10 transfers the pressing pressure of the stamp 15 applied in the axial direction 6 by deformation to the powdery material 5 compacted by the stamp 15 in the radial direction 9.

When the green body 1 relaxes, that is to say when the ram 15 moves back, the first press jacket 10 springs back in the axial direction 6 into an initial shape. This springback is significantly stronger than a springback of the green compact 1. Due to the friction between the first press jacket 10 and the powdered material 5, a spring also occurs on the first end face 7 of the green compact 1 facing the punch 15, in the radial direction 9 into the elastically deformable Material of the first press jacket 10 protruding edge (not shown here). During the pressing of the powdered material 5, e.g. Frictional forces between the first press jacket 10 and the green body 1, which are not reduced even if the first press jacket 10 springs back into its original shape. These circumstances mean that the green compact 1 can fail as part of the relaxation as a result of the shearing forces acting on the green compact 1 .

3 shows a first embodiment variant of a press 2 in a side view in section, during step a) of the method. 4 shows the press 2 3 in a sectional side view, during steps b) and c) of the method. 5 shows the press 2 3 and 4 in a sectional side view, during steps d), e) and f) of the method. 6 shows the press 2 3 until 5 in a sectional side view, during step g) of the method.

7 shows the press 2 3 until 6 in a sectional side view, during step g) of the method. 8th shows the press 2 3 until 7 in a sectional side view, during step h) of the method. the 3 until 8th are described together below.

The press 2 comprises a die 3 with a receiving volume 4 for a powdered material 5. The receiving volume 4 extends along an axial direction 6 between a first end face 7 and a second end face 8. The press 2 comprises a first closing element 13 for closing the first End face 7 and for compressing the material 5, a second closing element 14 for closing the second end face 8 and for compressing the material 5, a punch 15 which, relative to the die 3, is at least between an initial position 16 (see 3 , 4 , 6 , 7 and 8th ) and a pressing position 17 (see 5 ) can be moved, a core rod 21 and an ejector 19 (the second closing element 14).

The die 3 has an annular first pressing jacket 10 which is arranged outside of the receiving volume 4 in a radial direction 9 running transversely to the axial direction 6 and adjoins the receiving volume 4 and is formed from a non-elastically deformable first material. The die 3 also has a second press jacket 11 which is arranged adjacent to the first press jacket 10 in the radial direction 9 and is formed from an elastically deformable second material. In addition, the die 3 comprises a press ring 12 , which is arranged in the radial direction 9 adjacent to the group comprising the first press jacket 10 , the second press jacket 11 , the core rod 21 and the receiving volume 4 . The first press jacket 10 is arranged along the radial direction 9 between the receiving volume 4 and the second press jacket 11 .

The receiving volume 4 extends along a circumferential direction 20 around the 21 core rod of the press 2, which is stationarily positioned during the displacement of the second material by the punch 15.

The first closing element 13 and the second closing element 14 can each be moved relative to the receiving volume 4 . The closing elements 13, 14 are each used as a stamp for pressing of the material 5 used. The first closing element 13 is also used as an ejector 19 .

The first press jacket 10 is ring-shaped and hollow-cylindrical and is arranged outside of the receiving volume 4 in a radial direction 9 running transversely to the axial direction 6 . The first press jacket 10 is arranged adjacent to the receiving volume 4 . The first press cover 10 is formed from a non-elastically deformable first material. The first press jacket 10 is arranged directly adjacent to the receiving volume 4, so that it can press the powdered material 5 or the green body 1 (only in 6 ) contacted. The first press jacket 10 extends along the axial direction 6 over the first end face 7 and over the second end face 8 of the receiving volume 4 .

The first closing element 13 and the second closing element 14 extend in a radial direction 9 only over the receiving volume 4 and are guided through the core rod 21 and the first press jacket 10 in relation to the radial direction 9 .

The second press jacket 11 is arranged directly adjacent to the first press jacket 10 in the radial direction 9 . The second press jacket 11 contacts the first press jacket 10. The second press jacket 11 is formed from an elastically deformable second material. During steps d), e) and f), the second press jacket 11 extends along the axial direction 6 over the first end face 7 and over the second end face 8 of the receiving volume 4 .

The second press jacket 11 is ring-shaped and designed as a hollow cylinder. The second press jacket 11 is arranged between the press ring 12 and the first press jacket 10 in the radial direction 9 .

The compression ring 12 extends along the axial direction 6 beyond the second end face 8 of the receiving volume 4 and beyond the first end face 7 .

The first press jacket 10 is arranged along the radial direction 9 between the receiving volume 4 and the second press jacket 11 .

In step a), the press 2 is prepared, the receiving volume 4 being closed on the first end face 7 by the first closing element 13 and the stamp 15 being arranged in the starting position 16 (see FIG 3 ). The first closing element 13 thus forms the first end face 7 of the receiving volume 4. The receiving volume 4 is designed to be closed except for the filling opening for the powdered material 5, the second end face 8. The receiving volume 4 is defined by the components of the press 2, i.e. by the first press jacket 10, the closing elements 13, 14 and a core rod 21. The receiving volume 4 comprises a larger volume than the volume of the green compact 1 produced, since this is the result of pressing and compacting of the powdery material 5 is produced. The end faces 7, 8 are moved towards one another along the axial direction 6 during steps d), e) and f).

In step b), the powdery material 5 is filled into the receiving volume 4 (see 4 ). The filling takes place via the second end face 8.

In step c), the second end face 8 is closed by the second closing element 14 (see FIG 4 ). The second closing element 14 forms the second end face 8 of the accommodation volume 4. The volume of the accommodation volume 4 is thus defined in step c). The powdered material 5 fills the receiving volume 4 completely.

In step d), the closing elements 13, 14 are moved and the material 5 is pressed. In the process, the receiving volume 4 is successively reduced.

In step e), the stamp 15 is moved into the pressing position 17 (see FIG 5 ). The stamp 15 moves along the axial direction 6.

The punch 15 in the pressing position 17 contacts the second press jacket 11 and thereby at least partially displaces the second material, so that a pressing force of the punch 15 is transmitted to the second press jacket 11 and, starting therefrom, via the first press jacket 10 to the powdered material 5.

The contacting of the second material of the second press jacket 11 takes place successively during the movement of the stamp 15. The second material is displaced to an increasing extent during the process. The displaced volume of the second material is now used to support the first press jacket 10, which is acted upon by the pressing force applied by the closing elements 13, 14 via the compacted material 5. The first material of the first press cover 10 can therefore not give way in the radial direction 9 or the pressing force of the closing elements 13, 14, but is supported by the second material with a supporting force. If necessary, the first press jacket 10 is moved towards the receiving volume 4 and reduces it.

Via the first press jacket 10 (or via the second press jacket 11) and the closing element ments 13, 14, the material 5 is pressed and increasingly compacted.

In step f), the material 5 is pressed to form a green compact 1, with the stamp 15 being or being able to be moved independently of the closing elements 13, 14 (see FIG 5 ).

The receiving volume 4 is reduced exclusively or essentially by moving the closing elements 13 , 14 . A distance between the end faces 7, 8 changes during step d) or additionally during step e), i.e. during the displacement of the second material by the punch 15.

In the pressing position 17 , the stamp 15 is arranged at a distance from the first press jacket 10 in the radial direction 9 . The plunger 15 contacts the pressing ring 12 or is arranged adjacent to it in the pressing position 17 .

After step f), in a step g) the stamp 15 is moved from the pressing position 17 back to the starting position 16 ( 6 ). The second material deforms back and the first press jacket 10 is arranged at a distance from the green body 1 . In the process, the green body 1 is relaxed exclusively in the radial direction 9. Due to the usual springback of the green body 1, the green body 1 detaches itself from the wall of the core rod 21 by itself. During step g), the closing elements 13, 14 are not moved.

Alternatively, after step f), in a step g), the green compact 1 can be successively relaxed by moving the punch 15 and at least one of the closing elements 13, 14, with relaxation of the green compact 1 taking place both in the radial direction 9 and in the axial direction 6 he follows ( 6 and 7 ). A slackening of the green compact 1 can be controlled by a coordinated movement of the stamp 15 and the closing elements 13, 14, so that stresses in the green compact 1 can be successively reduced.

In 7 it is shown that the second closing element 14 is moved along the axial direction 6 and releases the second end face 8 of the accommodation volume 4 .

The first closing element 13 is at least partially designed as an ejector 19, so that after step g) the green body 1 can be displaced in a further step h) by the ejector 19 along the axial direction 6 ( 8th ).

The press 2 has a system 22 for data processing, e.g. B. a control unit, which is suitably equipped, configured or programmed to carry out the method described or which executes the method (see 3 ).

9 12 shows a second variant embodiment of a press 2 in a sectional side view, during steps d), e) and f) of the method. On the remarks on the 3 until 8th is referenced.

In contrast to the first embodiment variant, the press 2 comprises a plurality of stamps 15 which are used in step d) to displace the second material. The stamps 15 can be moved simultaneously or in a fixed order. The stamps 15 are moved from different directions, namely from different axial directions 6 and from the radial direction 9, into the second material.

As in the first embodiment variant, the stamps 15 have an end face 18 that contacts the second material in step e), the end face 18 having a planar contour in each case. The second material is displaced in the radial direction 9 towards the first press casing 10 due to the flat contour of the end face of the ram 15 moving in the radial direction 9 .

Reference List

1

greenling

2

Press

3

die

4

recording volume

5

material

6

axial direction

7

first face

8th

second face

9

radial direction

10

first press coat

11

second press coat

12

press ring

13

first closing element

14

second closing element

15

Rubber stamp

16

starting position

17

pressing position

18

face

19

ejector

20

circumferential direction

21

core rod

22

system

Claims (15)

Method for producing at least one green compact (1) with a press (2), the press (2) comprising at least • a die (3) with a receiving volume (4) for a powdered material (5); wherein the receiving volume (4) extends along an axial direction (6) between a first end face (7) and a second end face (8); where the die (3) o an annular first press jacket (10) arranged in a radial direction (9) running transversely to the axial direction (6) inside or outside the receiving volume (4) and adjoining the receiving volume (4) and made of a non-elastically deformable first material is formed; o a second press jacket (11) which is arranged adjacent to the first press jacket (10) in the radial direction (9) and is formed from an elastically deformable second material; such as ◯ a pressing ring (12) arranged in the radial direction (9) adjacent to the group comprising the first pressing shell (10), the second pressing shell (11) and the receiving volume (4); having; wherein the first press jacket (10) is arranged along the radial direction (9) between the receiving volume (4) and the second press jacket (11); • at least one first closing element (13) for closing the first end face (7) and for pressing the material; • at least one second closing element (14) for closing the second end face (8) and for pressing the material; • at least one stamp (15) which can be moved relative to the die (3) at least between an initial position (16) and a pressing position (17); the method comprising at least the following steps: a) providing the press (2), the receiving volume (4) being closed on the first end face (7) by the first closing element (13) and the ram (15) being arranged in the starting position (16); b) filling the powdered material (5) into the receiving volume (4); c) closing the second end face (8) by the second closing element (14); d) moving the closing elements and pressing the material; e) Movement of the stamp (15) into the pressing position (17), the stamp (15) in the pressing position (17) contacting the second press jacket (11) and thereby at least partially displacing the second material, so that a pressing force of the stamp ( 15) is transferred to the second press jacket (11) and proceeding therefrom via the first press jacket (10) to the powdery material (5); f) pressing the material (5) to form a green compact (1), the stamp being able to be moved independently of the closing elements. procedure after Claim 1 , wherein the at least one stamp (15) in the pressing position (17) is arranged at a distance from the first press jacket (10). A method according to any one of the preceding claims, wherein the second material comprises a polymeric material. Method according to one of the preceding claims, wherein after step f) in a step g) the at least one stamp (15) is moved from the pressing position (17) back to the starting position (16); the green body (1) being relaxed only in the radial direction (9). Method according to any of the preceding patent claims 1 until 3 , wherein after step f) in a step g) the green compact (1) is successively relaxed by moving the at least one stamp (15) and at least one of the closing elements (13, 14), wherein the green compact (1) is relaxed both in the radial direction (9) as well as in the axial direction (6). Method according to one of the preceding claims, wherein during the displacement of the second material by the punch (15) the closing elements (13, 14) are stationarily positioned. Method according to any of the preceding patent claims 1 until 4 , Steps d) and e) being carried out at least partially in parallel in terms of time. Method according to one of the preceding claims, wherein the press (2) comprises a plurality of stamps (15) which are used in step e) to displace the second material. Method according to one of the preceding claims, wherein the at least one punch (15) has an end face (18) contacting the second material in step e), the end face (18) having a contour through which the second material flows in the radial direction (9) towards the first press cover (10) is displaced. Method according to one of the preceding claims, wherein at least one of the closing elements (13, 14) is at least partially designed as an ejector (19), so that the green ling (1) after step f) in a further step h) by the ejector (19) along the axial direction (6) is displaceable. Method according to one of the preceding patent claims, in which the receiving volume (4) is ring-shaped. Method according to one of the preceding claims, wherein the receiving volume (4) is arranged in the radial direction (9) within the first press jacket (10). procedure after Claim 11 wherein the receiving volume (4) extends along a circumferential direction (20) around at least one core rod (21) of the press (2), which is stationarily positioned during the displacement of the second material by the at least one punch (15). Press (2) for producing at least one green compact (1), at least comprising • a die (3) with a receiving volume (4) for a powdered material (5); wherein the receiving volume (4) extends along an axial direction (6) between a first end face (7) and a second end face (8); where the die (3) ◯ a radial direction (9) running transversely to the axial direction (6) inside or outside the receiving volume (4) and adjoining the receiving volume (4) annular first press jacket (10) made of a non-elastically deformable first material is formed; o a second press jacket (11) which is arranged adjacent to the first press jacket (10) in the radial direction (9) and is formed from an elastically deformable second material; such as ◯ a press ring (12) arranged in the radial direction (9) adjacent to the group comprising the first press jacket (10), the second press jacket (11) and the receiving volume (4); having; wherein the first press jacket (10) is arranged along the radial direction (9) between the receiving volume (4) and the second press jacket (11); • at least one first closing element (13) for closing the first end face (7) and for pressing the material; • at least one second closing element (14) for closing the second end face (8) and for pressing the material; • at least one punch (15) which can be moved relative to the die (3) at least between a starting position (16) and a pressing position (17) and is independent of the closing elements (13, 14) and is arranged such that it is in the pressing position (17) at least partially displaces the second material. Press (2) after Claim 14 , wherein the press (2) has a system (22) for data processing for carrying out a method according to one of the preceding patent claims 1 until 13 is suitably equipped.

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